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Old 10-04-2012, 09:05 AM   #1
555*
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Member#: 82744
Join Date: Mar 2005
Chapter/Region: South East
Location: Panama City, FL
Vehicle:
2003 WRX
WRB

Question Idle surge and no accel in boost

03 WRX
COBB AP 93 Stage 2 tune
Catless TBE
Gutted STI up pipe
AEM short intake (out of the box tune)
STI TMIC

Problem:
Car sat for a week and went to start it and it fired up and idled pretty normal and after about a minute or 2 it started surging from about 500 rpm-1000. Car drives fine if its under boost. If I give it gas and get it into mid boost it just feels like I'm pulling a dump truck behind me.

Attempted problem solving:
Did the ol carb cleaner test to see if there were any vacuum leaks around couplings, ends of hoses, etc. Probably even over did it but no changes in idle. Cleaned MAF which was not dirty at all. Unpluged MAF, car died. Not showing any codes either. Cleaned the IACV and replaced the gasket which looked fine anyways. No dice. Tried swapping out the IACV for a known working one. Again no worky. Unplugged IACV, idle increased to about 1000ish and stayed steady. Fresh tank of 93 oct gas. Installed a Hallman Boost controller last night, since my pro tuner prefers tuning with that and it didn't help either (didn't expect it to). Any other suggestions?

Last edited by 555*; 10-05-2012 at 12:56 PM.
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Old 10-04-2012, 09:46 PM   #2
555*
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Vehicle:
2003 WRX
WRB

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Would resetting the ECU (pulling ground off and hitting the brakes) cause this?
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Old 10-08-2012, 09:05 AM   #3
555*
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Location: Panama City, FL
Vehicle:
2003 WRX
WRB

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Well I checked fuel psi and I'm steady at 35 with the vacuum hose still hooked up on the FPR. I unhooked my guage line and orange gas came out :/. I just filed it from a 1/4 tank to full with fresh 93 the other day.
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Old 10-08-2012, 10:09 AM   #4
art@grimmspeed
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It really does sound like either the IACV or a vac leak. I would at least give resetting the ECU a shot. This one has me puzzled as well........off to do research.
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Old 10-08-2012, 10:14 AM   #5
555*
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Yeah, I reset it, like 5 times. Did the whole, unhooking ground wire and hitting the brakes deal. It literally ran fine and sat for a week and is doing this. I was told using propane to find a vacuum leak works better.

I'm getting fuel cut at random rpms too. If I sit in the driveway and just WOT it, it will most of the time be okay and then BAM, 3500 RPM it just dies or 4500. Nothing in particular.

Tried driving it, moderate throttle and it goes fine but as soon as I WOT it, it sputters and just shuts down even at WOT. I'm sure it is something really stupid.

Generaly, starts up and runs great, till I blip the throttle or it runs for a minute and then the surging starts.

Maybe I'll try cleaning the IACV again but I thought I did a pretty good job of it last time.

Last edited by 555*; 10-08-2012 at 10:20 AM.
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Old 10-10-2012, 09:00 PM   #6
555*
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2003 WRX
WRB

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Learning view shows:

DTC TEMPORARY: P0500 VEHICLE SPEED SENSOR A
DTC TEMPORARY: P1591 NEUTRAL POS. SWITCH LOW INPUT (AT)
DTC TEMPORARY: P0480 RADIATOR FAN RELAY 1 LOW
DTC TEMPORARY: P0136 REAR O2 SENSOR CIRCUIT MALFUNCTION
DTC TEMPORARY: P1230 FUEL PUMP CONTROL UNIT MALFUNCTION
DTC TEMPORARY: P0131 FRONT O2 SENSOR LOW INPUT
DTC TEMPORARY: P0132 FRONT O2 SENSOR HIGH INPUT
DTC TEMPORARY: P0037 REAR O2 SENSOR LOW INPUT
DTC TEMPORARY: P0245 WASTEGATE SOLENOID A LOW
DTC TEMPORARY: P1096 TGV SIGNAL 2 (OPEN)
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Old 10-11-2012, 09:41 AM   #7
ShinjiML
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Almost sounds like the green flash connectors are connected....
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Old 10-11-2012, 09:48 AM   #8
555*
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2003 WRX
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Green plugs under the dash are disconnected. I thought the same and checked.
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Old 10-22-2012, 08:56 AM   #9
555*
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2003 WRX
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Down to 3 codes and out of test mode now. Not as much surging idle but im still getting fuel cut at 3-4 psi. Waiting on my new fuel pump install kit to get here and ill put the new walbro in.
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Old 10-23-2012, 07:10 AM   #10
555*
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Location: Panama City, FL
Vehicle:
2003 WRX
WRB

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Turned out to be a bad fuel pump. Put a new walbro in and it runs great now. It had some china made pump in it. The walbro is about 3 times louder hah. Boosts with no fuel cuts what so ever. Yay.
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